What type of biometric error occurs if a user logs into another customer's account after scanning their fingerprint?

The situation described involves a user mistakenly gaining access to another customer's account using their fingerprint, which relates to the concept of biometric error types.

A Type 2 error, also known as a false acceptance rate (FAR), occurs when a biometric system incorrectly identifies an individual as a match for another's biometric data. In this scenario, it indicates that the fingerprint scanner misidentified the fingerprint belonging to one user as belonging to another user, allowing unauthorized access. This is a significant security concern in systems that rely on biometric authentication, as it means that the system accepted an incorrect biometric sample as valid.

This is different from Type 1 errors (false rejection), where a legitimate user's biometric credential is mistakenly rejected, preventing access. Type 3 errors typically pertain to biometric systems that may relate to specific applications and are not standardized like Type 1 and Type 2 errors. Type 4 errors are not officially recognized in the common nomenclature of biometric errors.

Thus, identifying that the user was allowed access to another customer's account due to incorrect biometric recognition is indicative of a Type 2 error. This understanding is critical for improving biometric system designs and enhancing their security measures.